LONDON, ENGLAND - HSBC chairman Stephen Green is quitting to become a trade minister in Britain's coalition government, the bank and Downing Street announced on Tuesday.

Green will take up the job early next year after leaving HSBC before the end of 2010.

Prime Minister David Cameron said he was "delighted" to appoint Green to a "vital role."

"With Stephen's experience and expertise, I know he will make an invaluable contribution towards this crucial agenda, helping to drive strong economic growth in the UK," Cameron added.

Green will join Britain's appointed upper parliamentary chamber the House of Lords in order to serve in government. He himself described the unpaid appointment as an "honour."

"In an increasingly competitive and international world, trade and investment are ever more critical to Britain's economic success and I am delighted to be joining the government at this exciting and challenging time," he said.

HSBC said its non-executive directors had been looking at the issue of replacing Green "for some months."

It added: "It was always the board's intention that it would be in a position to approve a successor to Mr Green before the end of the year, and that timetable remains on schedule."